Fuel Temperature Sensor Failure?

Fuel Temperature Sensor Failure?

DD in Volvo 770 Getting a Fuel Temp Sensor error

davelinde
23 February 2011
08:40 AM
I have searched far and wide and just don't seem to be able to find out exactly where the fuel temperature sensor is located.  I think I recall someone mentioning that it was towards the back of the Detroit engine.  I see something with some wires back on the turbo side and mounted in a braided steel jacketed line.

My problem is that more frequently I am getting a fuel temp sensor communications error on my Diagnostic display.  This happens without regard to the actual ambient temperatures winter or summer.  I suspect it is the sensor but I have been unable to find the specifics about where it is located and if I can check it with an ohmmeter like many of the other engine sensors.  If so, what resistance should I see on a good sensor.

I have not been able to find any reference to it in any of my documentation so I must be looking for the wrong thing or in the wrong place.  I don't even see it on Mark's schematics.

It occurs to me that I should ask if this error indicates any sort of other problem that might be in play, like fuel pump, injectors, etc.?  I don't want to risk damage by running much longer like this.  I am presuming it may be the cause for my mpg going down, though.  In any event, it is now time to fix it.

This is a 2000 Volvo 770 with the DD12 engine.  The problem has been there for more than a year but only about 2000 miles and just results in a "check engine at next stop" notification.  Up until this year, it might not show up but once every couple of hundred miles.  Now, it pops up probably once every 40-80 miles.

The diagnostics readout is:
MID 128
PID 174
FMI 3
inactive. Sum 133I

MID 128
PID 091
FMI 4
inactive. Sum 1 II

RESET ALL
THEN:
ENGINE FUEL TEMP FAULT
ELECTRICAL FAULTN. Sum. 1 I

Thoughts?
Emery

L'iil Black Dog
23 February 2011
03:16 PM
Emery,
You have a 12.7 series 60?  If so I have read that this sensor is a "Volvo only" option and is located I believe on the secondary filter head or base?  And you are correct about this leading to your drop in fuel mileage.  Please use the search on the " Trucker's forums" to find out the fix. From what I remember it is not allowing the injectors to function correctly thus the poor fuel mileage, probably have some vibration also?
Good Luck
Curt
roadfitter
23 February 2011
11:14 PM
Emery
I would suggest calling "DD" and ask about the codes.  I would also stop by my local Volvo dealer 1) they can tell you if you even have such a sensor. 2) how much it is and most importantly, print you out a picture of where it is so you'll know how to get at it.  KW has always been VERY good about that type of help for me!  I just spent 2 days and some BUCK'S at the "DD" store.  Long story short, my mpg had also fallen off 2 mpg, with more soot also.  They said a leek in the "Charge Air" could be part of the problem.  With my situation it was really good
that I went in to have them check, my charge air was fine.  That was one of the things the last owner replaced about 30K miles ago.  Part of my issue could be in the "exhaust waist gate valve" sticking mostly due to lack of use/not enough load.  These rigs are really complex so some time you just have to go to the MAN .Good luck and happy hunting!!!
In The Faith
roadfitter
Emery Nash
24 February 2011
11:28 AM
Thanks guys,
I have mostly been there and done that but so far, my "local" Volvo dealer has been off target on every problem diagnosis I have taken it to them for.  This includes: Worn out U joint carrier ("oh, that's ok"), Bad range shift solenoid ("your xy Shifter needs to be replaced"), Worn
out drag link ("I did a complete steering and front end checkout and all the links and kingpins are just fine"), Turn on the Automatic VORAD braking feature ("oh, you have to buy a $2000 feature card before you can turn that on").

In each case, my own diagnosis found none of the problems being caused by their diagnosed prognosis so I am certain that I have to run the problem identification and diagnosis right down to the specific component.  To that end, I really need a set of shop manuals for the Volvo (which I have a shortened version) that includes full schematics, troubleshooting manuals, etc.  Some are freely available on RoadRanger for the Eaton equipment but Detroit Engine - Volvo Specific features/ modifications information just does not seem to be "out there".

If anyone even has the specifics about the location of the sensor, I can just pull the wiring and see if what I think is the sensor really is it.  If I have the resistance specs, I can test it before just Easter egging the thing like some folks can afford to do.  Before I buy a part, I really want to know that it is what is bad but these sensors have multiple ways of failing and when they get marginal, the symptoms can be all over the place.

Thanks for the info so far, guys.

L'iil Black Dog
24 February 2011
01:22 PM
Emery,
Try this TruckersReport.com
Curt
Emery Nash
26 February 2011
07:01 AM
It turns out that the fuel temperature sensor is located on the rearward fuel filter housing so it does not appear on the Detroit or Volvo parts lists as part of the engine.

I had to contact Detroit Diesel to find it. Looks like a $60+ part, if this is what I really need.  I need to check out the wiring, first, and then test the sensor, still looking for info on how to do that, forgot to ask the DD guy.  I was so excited at just finding out where it is located, I got giddy.